Actual source code: ex6f.F90
1: program main
2: #include <petsc/finclude/petscvec.h>
3: use petscvec
5: implicit none
7: PetscErrorCode ierr
8: PetscMPIInt :: mySize
9: integer :: fd
10: PetscInt :: i,sz
11: PetscInt,parameter :: m = 10
12: PetscInt,parameter :: one = 1
13: PetscInt, allocatable,dimension(:) :: t
14: PetscScalar, pointer, dimension(:) :: avec
15: PetscScalar, pointer, dimension(:) :: array
16: Vec vec
17: PetscViewer view_out,view_in
18: character(len=256) :: outstring
19: PetscBool :: flg
21: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
22: if (ierr /= 0) then
23: print*,'PetscInitialize failed'
24: stop
25: endif
27: call MPI_Comm_size(PETSC_COMM_WORLD,mySize,ierr)
29: if (mySize /= 1) then
30: SETERRA(PETSC_COMM_SELF,PETSC_ERR_WRONG_MPI_SIZE,"This is a uniprocessor example only!")
31: endif
33: call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,"-m",m,flg,ierr);CHKERRA(ierr)
35: ! ----------------------------------------------------------------------
36: ! PART 1: Write some data to a file in binary format
37: ! ----------------------------------------------------------------------
39: ! Allocate array and set values
41: allocate(array(0:m-1))
42: do i=0,m-1
43: array(i) = real(i)*10.0
44: end do
46: allocate(t(1))
47: t(1) = m
48: ! Open viewer for binary output
49: call PetscViewerBinaryOpen(PETSC_COMM_SELF,"input.dat",FILE_MODE_WRITE,view_out,ierr);CHKERRA(ierr)
50: call PetscViewerBinaryGetDescriptor(view_out,fd,ierr);CHKERRA(ierr)
52: ! Write binary output
53: call PetscBinaryWrite(fd,t,one,PETSC_INT,ierr);CHKERRA(ierr)
54: call PetscBinaryWrite(fd,array,m,PETSC_SCALAR,ierr);CHKERRA(ierr)
56: ! Destroy the output viewer and work array
57: call PetscViewerDestroy(view_out,ierr);CHKERRA(ierr)
58: deallocate(array)
60: ! ----------------------------------------------------------------------
61: ! PART 2: Read data from file and form a vector
62: ! ----------------------------------------------------------------------
64: ! Open input binary viewer
65: call PetscViewerBinaryOpen(PETSC_COMM_SELF,"input.dat",FILE_MODE_READ,view_in,ierr);CHKERRA(ierr)
66: call PetscViewerBinaryGetDescriptor(view_in,fd,ierr);CHKERRA(ierr)
68: ! Create vector and get pointer to data space
69: call VecCreate(PETSC_COMM_SELF,vec,ierr);CHKERRA(ierr)
70: call VecSetSizes(vec,PETSC_DECIDE,m,ierr);CHKERRA(ierr)
72: call VecSetFromOptions(vec,ierr);CHKERRA(ierr)
74: call VecGetArrayF90(vec,avec,ierr);CHKERRA(ierr)
76: ! Read data into vector
77: call PetscBinaryRead(fd,t,one,PETSC_NULL_INTEGER,PETSC_INT,ierr);CHKERRA(ierr)
78: sz=t(1)
80: if (sz <= 0) then
81: SETERRA(PETSC_COMM_SELF,PETSC_ERR_USER,"Error: Must have array length > 0")
82: endif
84: write(outstring,'(a,i2.2,a)') "reading data in binary from input.dat, sz =", sz, " ...\n"
85: call PetscPrintf(PETSC_COMM_SELF,trim(outstring),ierr);CHKERRA(ierr)
87: call PetscBinaryRead(fd,avec,sz,PETSC_NULL_INTEGER,PETSC_SCALAR,ierr);CHKERRA(ierr)
89: ! View vector
90: call VecRestoreArrayF90(vec,avec,ierr);CHKERRA(ierr)
91: call VecView(vec,PETSC_VIEWER_STDOUT_SELF,ierr);CHKERRA(ierr)
93: ! Free data structures
94: deallocate(t)
95: call VecDestroy(vec,ierr);CHKERRA(ierr)
96: call PetscViewerDestroy(view_in,ierr);CHKERRA(ierr)
97: call PetscFinalize(ierr);CHKERRA(ierr)
99: end program
101: !/*TEST
102: !
103: ! test:
104: ! output_file: output/ex6_1.out
105: !
106: !TEST*/